The Shoulder Rotator Cuff
I want to explain in a little more detail what the rotator cuff muscles actually do within the shoulder joint. I want to go on to show why the rotator cuff muscles have such an important role to play in shoulder stability.
Bones of the shoulderThe rotator cuff muscles are important in shoulder movements and in maintaining shoulder joint (Glenohumeral Joint) stability. The shoulder comprises of three bones, the clavicle, scapula and humerus and these are shown below.
The rotator cuff muscles arise from the scapula (shoulder blade).
They then connect to the head of the Humerus forming a "cuff" at the shoulder joint. The diagram below shows the Humerus or upper arm bone. It is the Humeral head that attaches to the rotator cuff muscles.
The rotator cuff muscles are designed to hold the head of the Humerus in the small and shallow Glenoid Fossa or more commonly it is known as the Glenoid Cavity of the Scapula. This is shown in the diagram below.
So what exactly does the shoulder do and what connection is there between the shoulder rotator cuff and the various bones and rotator cuff muscles?
The information above is a general overview of the workings of the shoulder rotator cuff anatomy. I now want to go into a little more detail.
What do the rotator cuff muscles do?The primary role of the rotator cuff muscles within the shoulder rotator cuff link is quite simple. It is to place the upper extremities, which are the arms and hands, in positions that allow them to function fully.
If you think about it, the arms and the hands can assume an almost infinite number of positions. No matter in which three dimensional perspective you want the hands and arms to move, it can be done.
To allow this free range of motion the shoulder joint is arranged as a semi or modified "ball and socket" joint. It is capable of movement in all three planes - A bit more information about body planes can be found in the next section on the primary roles of the muscles of the rotator cuff.
The problem with all this movement is that as a result the shoulder joint sacrifices some of its stability, when compared to say the hip joint. The shoulder joint lacks the deep full socket and broader socket surface area compared to the hip joint and socket. So instead of a fairly closed ball and socket joint like the hip it is more of a "golf ball on a tee" joint.
The humeral head moves with the much smaller and shallow almost saucer like glenoid fossa, shown above. What is not so clear in the diagram of the glenoid fossa above is that it is located on the scapula or shoulder blade.
The result is that the shoulder joint is not as stable as the hip joint, it is said to be more dynamically stable than statically stable
The major function of the rotator cuff muscles is therefore to work together to allow the arms to move freely. They do this whilst at the same time constantly pulling the head of the humerus both downward and inward within the glenoid fossa.
It is important to remember that the humeral head is actually three to four times larger than the glenoid fossa. As a result only about 25% of the humeral head is actually in contact with the glenoid fossa at any one moment in time.
Powerful Restrictive properties
That is why it is so important to have a strong and healthy rotator cuff muscles. The rotator cuff muscles have to have enough power to stop the humeral head from moving. Without a strong shoulder rotator cuff connection the humeral head would not be held securely.
From the Shoulder Rotator Cuff Connection to Rotator Cuff Exercises
Sign Up for Your Free Mini Course Now!
Search My Site:Free Rotator Cuff Health & Exercises Mini Course
Just enter your first name & e-mail address in the form below. You'll receive your first issue immediately in your email!
* * * * * * * * * * * * *
Heal your rotator cuff injury naturally with the best rotator cuff exercises...
Available for Immediate Download
Download Your Copy Here Now
* * * * * * * * * * * * *
Your kind donations will keep this Free Website and its related Newsletter going & growing...
Rotator Cuff Exercises Home Page | About Me | Contact Me | Donate | Privacy & Disclaimer | Rotator Cuff Exercises Book | SiteMap